Calculator for determining maximum cutting speeds of machine tools



June 26, 1951 R. EGLI 2,558,646

CALCULATOR FCR DETERMTNTNC MAXIMUM CUTTING SPEEDS OF MACHINE TOOLS FiledNov. 17, 1948 4 sheets-sheet 1 June 26, 1951 R. EGLI CALCULATOR FORDETERMINING MAXIMUM CUTTING SPEEDS OF MACHINE TOOLS 4 Sheets-Sheet 2Filed NOV. 17, 1948 June 26, 195] R. EGLI CALCULATOR FCRDETERMTNINC-MAXTMCM CUTTING sPEEDs CF MACHINE TooLs Fi'led Nov. 17, 19484 Sheets-Sheet 5 RMN u: f. fi LHBual uuu-|00; do; salnugw u! amg; BUNJOMJune 26, 195] R. EGLI CALCULATOR FOR DETERMININC MAXIMUM CUTTING ASPEEDS VOF MACHINE TOOLS Filed NOV. 17, 1948 4 Sheets-Sheet 4 PatentedJune 26, 1951 CALCULATOR FOR DETERMINING MAXI- i MUM CUTTING SPEEDS OFMACHINE TOOLS Rudolf Egli, Zurich, Switzerland, assigner of onehalf toReuge & Cie, Vaud, Switzerland, a firm Application November 17, 1948,Serial No. 60,566 In Switzerland December 2, 1947 2 Claims.

The present invention relates to calculating apparatus especially fordetermining the most economical working speeds and relevant times onmachine tools such as lathes, drilling machines, borers, millingmachines and the like operating by chip removal.

Heretofore the values relevant for an economical chip removal procedurethat is speed, feed and chip thickness (which three values willhereinafter be referred to together as Working conditions) and theworking times dependent thereon were calculated by means of extensivecollected working preparation and calculation information in tabular orIbook form with the help of calculating discs, nomograms, diagrams orother helping means. This requires on the one hand, collection andassembly of work-information and which on the other hand must be broughtinto useful form by technically skilled personnel by means of auxiliarycalculating apparatus.

The basis for correct machine operation and therefore of the cuttingoperating in itself, that is the collection of these papers relating tothe most economical working and calculating information were determinedfrom workshop experience and the results of experiments on chip removal.Exact natural basic laws have not heretofore been discovered. Theeffects of the various iniluences and their inter-relation can for themost part only be determined by practical experiments, for which purposealso only empirical basic laws can be determined. One can therefore onlyspeak of mathematical laws so far as one has found the conditions orinfluences under the same or similar assumptions and these must alwaysbe found in advance.

The conditions so found comprise for the most part those dependent onthe working conditions (speed, feed and chip thickness) Which occurunder the same or similar assumptions. The knowledge of these conditionsand effects and their expression in the form of a law, which lead to aneconomical employment of the tool and machine and their interdependenceon the operating conditions, is well known to the research engineer andspecialist, but in the workshop or factory they are known onlyincompletely or at most only by special study foreach specialapplication.

The object of the present invention is to pro- Vide an apparatus whichby simple adjustment of certain or desired values automatically showsthe most economical Working conditions on the basis of theabove-mentioned laws. Furthermore the apparatus also shows theappertaining machine times in directly visible form.

For various chip-forming types of work for example for turning, boring,milling and the like the construction of the apparatus is in principleFig. 3 a longitudinal section on line III-III,

Fig. 1J

Fig. 4 a section of the table applied to the large roller,

Fig. 5 a view of the screen applied to the cas- 111g,

Fig. 6 a view of the table on the small roller, and

Fig. 7 shows the instruction card with the necessary instructions.

In the constructional embodiment shown on the drawing, I is the baseplate on which rests a cylindrical housing 3 by means of two end plates2, which housing is concentric with the spindle 4 and is provided withnumerous Window apertures 5 of which the arrangement and purpose will befurther explained below. Over part of the outerl Wall of the casing 3 isdisposed a layer 6 of transparent material which prevents the entry ofdust and dirt through the windows 5 into the inside of the casing 3.Over the layer 6 is a screen II provided with window 5' `correspondingto the windows 5 and embodies in'- structional matter as shown on Fig.5. On the end faces of the housing 3 are the circular end plates l, 8 inwhich the spindle 4 is rotatably mounted. The left hand end (Fig. 3) ofthe spindle 4 carries the knurled adjusting ring 9 which is secured tothe spindle 4 by means of a pin IB. Within the casing 3 and immediatelyto the right (Fig. 3) against the plate l, is the large roller I2 whichis supported on the spindle 4 by means of the discs I3, I4. The rollerI2 which carries a table I5 (Figs. 3 and 4) is xed' to the spindle 4 sothat by adjustment of the adjusting ring 9 the large roller I2rotateswith it whereby the gures of the table I5 can be seen through thewindows 5, 5.

Notches I6 are provided on the outer side of the disc I3, whichcooperate with a ball I8 pressed by spring Il located under compressionwindows i 53a.

two discs 52;):53frelativelyto a windowof the.

screwing down the sleeve 24 on the thread 22 their small roller 20 ispressedagainst the disc lli so that it is operated with therlatter. Ifon'the other hand the sleeve 24 is screwed to' the right (Fig. 3) therollers l2, 20 can rotate independently. The roller 20 alsocarries:on.its;periph eral part, which is of the samediameterf astheilarge roller I2, a table 25 whichgis shown-.de-

veloped in Fig. 6 and of which` the guresare readable through thewindows 5, 5 of the housing 3 and through the screen ll. The roller-r25lis provided with a knurled adjustment flange2Sfwhichis"accessiblefthrough:an opening 2l in the housing 3 (Fig. 1) L"AibltfZS actuated by-'springZS` isy adaptedto cooperate with 'thersmall" roller; beingr engage- The'bolt-Eil" islocated inrasleeve'Slletinto theplatet and."

closedirornthe outsidefby meansfof a 'screw'l-BZ.

The sleeverSl'- embodies :a shoulderwsurfaoe against whichkone vendfrof'"the spring l23 `bears surface 2.34501:` thel boltf29zf' Therloading'of the' small roller 2D by the bolt 29 iszhowevermore powerfulthan that of the large roller JlZbythe spring loaded ball I8 whichalsoractsfas a bolt. Itis'lth'erefore possible;1with: lthex clamping4sleeve 24 free, for the large roller l2 to be rotated by remains atrest by the action of thebolt Z9 thereon; it. however the:.tworollersfll,4 2@ are coupled together by action on the clampingwsleevef 24;' v'the two rollersfcanberotated together while overcomingthe spring action of the bolt-r 29. The.distribution'ifofrthe fnotches'ltfcorresponds with that of the tablefl5y Fig'.v 4 and the I ballI8"ensures"'spacing alwayscorrectlyunder 1 thee-windows offthehousing 3v`and of Athe screenv definitefpositionsbyfthe: notches 29 so that thetwo" l" rollers..v cantabe f rotated, l' independently andcanFbefcoupledrin.predetermined positions bythe clamping "sleeve 24ffandxthen together rotated overs-.thev windowsfin*fthe/casingtand ofthe Twofcalculating 'discs-52,ff 53fware .mounted on. thezjsleeve5ffwhich is rotatableon` the spindles" 4.L The 'discsare.rotatablyadjustable-;by a .ring 5 loin: such f-a manner that saspring detent 54 ofmlthedisc'i 52"-'which isf keyed .to the sleeve 5l] lentersrecesses `55 offthe-disc 53 which is rotatable'fon' the fsleeve50;v The disc 53.-*is 'also subject` toethe influence rvof -detents 56-engaging the. housing wal-15T: The'detents 56 are weaker than.

the spring detent54. The` discs 52, l53 are used ini'thevusual way ascalculating discs provided. with .logarithmic scales,r` in vsuch mannerythat discf-52eindicates.the length of the workpiece in millimeters inwindow 52dA whilev the disc 53. is-ad-justedto thee-working time'perunitof lengthY (minutefper 100V millimeters) readable through Bysimultaneous rotationof the housing the time required .to-work on work-Vpieces.:ordifferent length can be read off.

Before the ymethod of `operation of the de` will be brieiiy made to theinformation set out on the tables l5, 25. The rst, shown in partialdevelopment in Fig. 4, embodies the column 4I for the running time inminutes for each 100 millimeter length of workpiece, the column 42showing the speed in revolutions per minute, the column 43 indicates the'type of metaly to be operated upon and the column 44 indicates thecutting speed for high speed steel tools. The reading of these values iseffected through the windows 46; 35 and 31, that is through the threelefthandwindows (Fig. 5) of the casing. Corresponding information isgiven in the columns 5l, 42a,v42-b,f45-and 44' for hard metal toolsVandare readable through the series of windows ard numbers, as`established inindustry, with.

As.v is `.known theproducts and quotients of standard numbers and denite.incremental steps.

also..their powersv arestill. standard ynumbers which can. be determinedwithout calculation, that is by reading from the table. The values of. vthe standard numbers are vdistributed onthe two f rollers l5and -withlanAincremental progres..y sionwhich fulillsrequirements and arearranged-..-

as .required inrelation to the adjustment or readingwindows. Byadjusting :the rollers relatively and then coupling themand moving-themtogether to a desired reading point` (window), a very large table. .isreduced .in simple manner to the smallest possible dimensions.V

A determination of themost economical operating `.conditions with thepresent apparatusby Way of example for turning, will vnow be carried.`

out.

1.1'I`he operating. lever 23 .is released whereby,l

thetwo rollers l2 and 2t' can. be rotated independently.

2. The small roller .20. is rotated bythe ilange.

26 .and the desired workinglife of the lathe tool in the sectionA. ofthe table 25 shown in Fig. 6,

is set. in the appropriate window 35, Fig. 5,' whereupon this position,is xed by .the bolt 29.

3.. The largeroller l2 isadjusted bytheknob. S and thework vmaterial tobe treated isselected-z so vthat it comes-beneaththe window 3l (Fig. 5).

Thisfposition iS-nxed by the catch I8 without the. position of the-smallroller 20 being altered since-1 asalready explained the Vspring128v isstronger :y

thanithespring I1.

4; Thereupon the handle 23 is operated to couple the two rollers I2, 20together.

5. By the adjusting ringV 9 the workpiecey diameter is set, thisdiameter being shown in` metal turning tool is used, the right handsection. (Fig. 5) is employed, and if a high .speed steel. tool is used,the readingisobtained onthe .left

hand side of the apparatus under the. corresponding window 5.

If for` example operation is with speedsteel,H

the. most economical rotational. speed. comes under the row of windows39 marked frotary.. speed whereupon according .to themethod of,

Since vboth rollersk working the corresponding window is selected andthe relevant feed and the maximum permissible depth of cut is readagainst this window.

This most economical working condition read oif on the scale (workingspeed) guarantees a working-life to the cutting tool (time until theedge of the tool must be again ground) as selected from the beginning;that is such as has been selected by previous experience (see theintroduction to the diagram Fig. 7).

Simultaneously the machining time can be read from the window 40 asshown in Fig. 5. This time applies for a workpiece of 100 mm. length. Ifthe workpiece is of a diiferent length the actual time is indicateddirectly by the multiplication device 52, 53.

My invention accomplishes the economical and rapid determination of thedesired working conditions for chip removing operations. It is clearthat the embodiment described herein may be modied or varied withoutdeparting from the scope of my invention and I wish, therefore, todefine my invention only by the following claims.

What I claim is:

1. A calculating machine comprising a cylindrical housing having aplurality of openings in its circumference and having closed ends, ashaft rotatably mounted Within said housing with its ends extendingexteriorly of said housing, a drum xed to said shaft within said housingand having a chart on its circumference viewable through certain of saidopenings, a roller rotatably mounted on said shaft Within said housingadjacent said drum, and having markings on its circumference viewablethrough other of said openings, said shaft being provided with anadjusting ring for rotating said drum, said housing being slotted toexpose a portion of said roller for rotation thereof, spring detentmeans between one end of said housing and said drum for releasablyholding said drum in one of a plurality of positions wherein portions ofsaid chart are aligned with said openings, spring detent means betweenthe other end Wall of said housing and said roller for releasablyholding said roller in one of a plurality of positions, and a sleevescrew threadedly mounted on said shaft adjacent said roller and movablewith respect to said shaft to axially move said roller into lockingcontact with said drum whereby said drum and said roller are rotatableas a unit.

2. A calculating machine comprising, a stationarily mounted cylinderhaving a plurality of openings in its circumference, a shaft rotatablymounted axially within said cylinder, a drum fixed to said shaft havingmarkings on its circumference viewable through said openings, a rollerrotatably mounted on said shaft adjacent said drum and having markingson its circumference viewable through said openings, spring detent meansassociated with said drum and said cylinder and with said roller andsaid cylinder to releasably hold said drum and said roller respectivelyin one of a plurality of positions wherein certain of said markingsalign with said openings, means for rotating said shaft and said drumindependently of said roller, said roller having an integral flange forrotating said roller independently of said drum, said cylinder beingslotted to expose said flange, said shaft being threaded at the endthereof adjacent said roller, and a sleeve threaded on said shaft andmovable with respect thereto to clamp said roller to said drum wherebysaid drum and said roller rotate as a unit.

RUDOLF EGLI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 823,426 Meilicke June 12, 19061,278,315 Drake Sept. 10, 1918 1,400,363 Kennedy et al Dec. 13, 19211,973,192 Woodbury Sept. 11, 1934 2,293,175 Ruhl et al Aug. 18, 1942

